Replies

1. 
   gary_gilbert | Feb 02, 1999 10:52pm | #1

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   Not so fast Flash, you gotta insulate too. Otherwise, you will just have very cold interior ceilings and walls. That, mixed with any sources of humidity, and you'll have mold collections and odd biology experiments. While we're on the topic, the insulation really needs to have good coverage for the previous mentioned reason as well as for the rule of thumb that an insulation envelope for a building can not have in excess of 10% to 15% voids without completely negating the whole insulation effort. Additionally, the 1 sq. ft. of free ventilation area to 150 sq. ft. of floor area being vented is a great goal to shoot for. Although all you really need to do is approach that number and you'll be, ""Damn free !""

2. 
   Guest_ | Feb 05, 1999 02:23am | #2

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   daFlash. Running proper vents--polystyrene vents- from soffit to ridge makes them the first condensing surface instead of the roof sheathing. Now escaping warm moist air leaking through the insulation condenses on the proper vent and you have a potential lawsuit on your hands.

   If ventilation is the answer to ice dams then how do you explain all the ice dams on houses with vented attics, attics vented according to the 1/150 ratio, on metal roofs, on roofs weith heat tapes, yes even on roofs with ridge/soffit vents? GeneL

1. 
   Guest_ | Feb 05, 1999 02:30am | #4

   *A simple analogy I've used when someone suggests that ventilation is the key to preventing ice dams: It's very important to ensure that you have a free-flowing basement floor drain in order to keep your leaking water heater from flooding the basement.Treat the symptom or the disease?

3. 
   Guest_ | Feb 05, 1999 02:30am | #3

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   To prevent ice dams...simple...the key is proper ventilation...soffit vents on the eaves...styrofoam vents in the attic between each rafter up to the ridge through the ridge vent. Object is to keep the whole roof cold.